Electrical musical instrument capable of producing percussion effects



March 5, 1957 J. M. HANERT 2,733,672

ELECTRICAL MUSICAL INSTRUMENT CAPABLE OF PRODUCING PERCUSSION EFFECTS Filed Sept. 9, 1955 tha v United States Patent T ELECTRICAL MUSICAL INSTRUMENT CAPABLE OF PRODUCING PERCUSSION EFFECTS John M. Hanert, Des Plaines, Ill., assignor to Hammond Organ Company, Chicago, III., a corporation .of Delaware The invention relates generally to electrical musical instruments such as those of the organ type, and more particularly to means for producing percussion effects.

It is a primary object of the invention to. provide means for introducing percussion effects in electronic musical instruments.

A further object is to provide an electronic musical instrument with relay energized means to alter or add to the musical tones produced thereby, an effect of, percussion, either by controlling the tone intensity envelope, by introducing random noise, or by utilizing the pulse generated upon closure of a switch as. a means to cause a thump or click upon initiation of the tone.

Other objects and advantages will become apparent from the following description, reference being had to the accompanying drawing.

The drawing is a schematic and block diagram or representative portions of an electrical musical instrument incorporating the invention.

In general, the invention comprises the utilization of a relay energized for a brief instant upon depression of a playing key, the'relay being effective either to control an operating potential upon a control tube or tubes, so as to cause a sudden percussive attack and subsequent decay of the tone, simulating the tones of the Xylophone, marimba, etc, to introduce random noise at the initiation of the tone production, to simulate the effect of a snare drum, or to utilize the pulse produced upon completion of a circuit to introduce a more or less tuned pulse at the initiation of the sounding of a tone, to produce an effect simulating that of the sound of Chinese blocks.

Generally speaking, the invention is adapted to be utilized as a part of an electronic musical instrument employing oscillators as tone signal generators, in which key operated switches are employed to supply plate current to the oscillators to cause them to commence oscillation. in such instruments it is customary to utilize time delay circuits to effect gradual increase in potential on the plate of the oscillator so that the latter will supply a signal of more or less gradually increasing amplitude, which in effect will cause a more or less gradual attack.

While there is no doubt as to the merit of producing tones having a gradual attack, it is frequently desirable for emphasis and contrast in the rendition of a musical selection, to produce tones having a sudden attack and possibly gradual decay to simulate tones of percussive musical instruments, such as the Xylophone and marimba, and also to produce tones having an attack portion including a component of noise to simulate the effect of a snare drum or other pitchless instruments. Upon other occasions it is desirable to produce tones commencing with a Chinese block-like attack, that is, a pulse of more or less recognizable pitch as the attack portion of the tone. These desiderata are accomplished by the invention now to be described.

Referring to the drawing, the instrument comprises a manual consisting of five or more octaves of keys 10, of which two are shown as representative of a complete 2,783,672 Patented Man 5, 1 957 manual. For each key, or a small plurality of keys, there is provided an oscillator 12 comprising a triode 14. Each of the keys 10 operates a switch 16 by which a B+ terminal, through a resistance R18, is connected to supply plate current to the oscillator. This connection is effected through a conductor 20 connected to resistor R18. This connection is made through a switch 16, a resistor R22, which has in parallel therewith a resistor R24, and capacitor C26 in series. The value of the resistor R24 is substantially less than that of R22, and as a result upon closure of the switch 16, the potential on the plate 28: of the triode 1'4'is increased rather rapidly to operating potential to insure quick starting of the oscillator.

A capacitor C30 connects the plate 28 to ground to store a portion of the charge transmitted through R24 and C26 during the starting period, after which the potential on the plate 28 is maintained at proper operating value by current transmitted through resistor R22.

The grid 32 of. the triode 14 is connected to a vibrato oscillator terminal 34 through a resistor R36. The vibrato oscillator being of the type shown in my prior Patent No. 2,645,968, provides a grid return circuit. The grid 32 is also connected through a capacitor C38 to a terminal 40 of a parallel resonant tuning circuit comprising an inductance L42 and a. capacitor C44. Flute type signals, in which the higher harmonics are substantially absent, are derived from the oscillator from the terminal 40 through a decoupling resistor R46 connected to an output terminal 48. String type signals, rich in harmonics, are derived. from the other terminal of the resonant circuit and supplied to an output terminal 50.

Whenever any of the keys 10 is depressed to close its switch 16, there occurs a voltage drop across resistor R18. This voltage drop is transmitted through, a capacitor CS2 to the grid 54 of one triode 56 of a double triode. This triode is normally biased to be conducting by virtue of the connection of its grid 54 to the B+ terminal through a relatively high value resistor R58. Thus whenever a key is depressed, a negative voltage pulse is transmitted to the grid 54 through the capacitor C52, thus temporarily biasing the triode 56 toward cutoif. The other half 60 of the twin triode has its grid 62 connected to the plate 64 of triode 56 through a capacitor C66.

Plate current is supplied to the triode 56 through a load resistor R68 so that when triode 56 is rendered less conductive upon decrease of the potential on its grid 54, a positive pulse is transmitted through capacitor C66 to the grid 62. The grid 62 is provided with a grid resister R70. However, the plate 72 of triode 6-!) is connected through series capacitor C72 and resistor. R74 to the grid 5 of triode 56 so that as plate 72 goes negative, it tends to operate on grid 54 to decrease the potential thereon, and thus bias the triode 56 to or toward cutoff. The triode 60 is supplied with current from a 13+ terminal of the power supply through a relay winding L76. The cathodes of triodes 56 and 60 are connected to ground through a common cathode resistor R78. Due to the fact that the grid of triode 56 is normally close to its cathode, in voltage, a considerable current will flow through R78, thus cutting off the triode 60. In operation, the circuits of tubes 56 and 60 are sensitive to negative impulses only to temporarily operate relay L76.

The relay coil L76, when energized, operates to close switches 80, 81, and 82. These individually or in any desired combination, by manual operation of tablets S6, 87, and 38, respectively.

Assuming that the tablet 86 has been operated and its associated switch 90. closed, the signals produced by the oscillators in response to operation of one or more keys 10 switches are effective will be supplied through terminals 48 if flute quality tones are desired, and through terminal 50 if string quality tones are desired. (All of the terminals 50 shown in the circuit diagram of the oscillators are connected directly to the terminal 50 shown in the central upper portion of the figure, and similarly all terminals 48 of the oscillators are directly connected to the terminal 48 shown in the central upper portion of the figure.)

The terminals 50 are connected to ground through a load resistor R90. When string signals are desired, a switch 92 is manually operated to connect the terminal 50 to the primary winding L94 of a transformer T96 through a decoupling resistor R98. Similarly, when flute quality signals are desired, a switch 100 is closed to connect the terminals 48 to the primary winding L94 through a resistor R102. 1

The end terminals of a secondary winding L104 of transformer T96 are respectively connected to control grids of triodes 106 and 107. The cathodes of these triodes are connected to ground and the plates are connected to the terminals of a primary winding L110 of a transformer T112, the center tap of primary L110 being connected to a 13+ terminal of the power supply.

A center tap 114 on the secondary L104 is connected to ground through a capacitor C116. This center tap is also connected to a terminal 118 through a relatively high value resistor R120 and is also connected to the conductor 122 through a relatively low value resistor R124. The conductor 122 leads to the contactor of switch 80.

The secondary L126 of transformer T112 is connected by a decoupling resistor R128 to the contact of switch 90, and the signal appearing across winding L126 is impressed upon a conductor 130. The latter is connected to an input load resistor R132 connected across the input terminals of an amplifier 134. The output of the amplifier, which may include suitable volume controls, is coupled to a speaker 136.

From the foregoing it will appear that Whenever one of the keys is depressed, closure of its switch 16 results in applying an operating potential on the plate of its associated triode 14, causing the oscillator to commence oscillating. In addition, the negative pulse resultant from the drop in potential across resistor R18 is transmitted to the grid 54, causing the triode 56 to become cutofif or at least to decrease plate current flow. This results in an increase in plate current flow in the triode 60, as a result of which the relay winding L76 is energized sufficiently to cause closure of its switches 80, 81, and 32. Capacitors C72 and C66 together with resistors R74 and R68 have time constants of approximately twenty milliseconds to afford reliable operation of the relay having the winding L76.

Closure of the switch 80 reduces the voltage on the center tap 114 very rapidly to a value determined by the voltage divider provided by resistor R120 and R124, and the time constant in conjunction with the capacitor C116. Thus the potential on the grids of triodes 106 and 107 is rapidly changed to a value at which these triodes conduct at the maximum desired amplitude. The signal thus transmitted to the amplifier 134 and translated into sound in speaker 136 will have a very rapid attack and a relatively slow decay, the latter being controlled by the value of R120 which commences at the instant that relay winding L76 is deenergized. As previously indicated, the interval during which the relay winding L76 is energized is of very short duration, so that the decay of the tone commences immediately after the termination of the attack portion of the tone intensity envelope. The tone will be of a decided percussive nature, the envelope being comparable to that of tones produced by a number of mechanical musical instruments, such as xylophones, chimes, marimba, and the like.

When thetablet 87 is operated to close its switch 140, the closure of the relay operated switch 81 is effective to control'the tone intensity envelope, or rather the char-- acter of the attack portion of the tone, produced upon 4 depression of a playing key. When a playing key is depressed, the relay winding L76 will be energized, as previously described, and the switch 81 closed to connect a conductor 142 to ground. This conductor is connected through a resistor R144 to the center tap 146 of the secondary of a transformer T148. This center tap 146 is connected to ground through a capacitor C150,

. and is also connected to a terminal 156 of the power supply upon which the potential is suificiently negative to cut off control tubes 154 and 155, the connection being made through a relatively high value resistor R158.

The primary of transformer T143 is connected to a random noise generator 160 so that whenever the conductor 142 is connected to ground by closure of this relay switch 141, a random noise signal will be impressed upon the grid of control tubes 154 and 155, and through the transformer T162 transmitted through decoupling resistor R164 and switch 140 to the signal collector conductor 130. It will be understood that resistor R144 is of much lower value than resistor R158, so that the attack will be relatively rapid and the signal derived from the random noise generator 160 will be heard from v the speaker 136 as a noise commencing with a sharp attack. When the relay is deenergized and the switch 81 opened, the noise signal will gradually decay and the efiect will be that of the swishing noise produced by a snare drum and similar random noise producing types of mechanical musical instruments.

The random noise generator 160 may be of-any suitable construction, but is preferably a superregenerative oscillator of the type shown in my prior Patent No. 2,432,- 152. It is desirable merely that this random noise generator produce signals extending throughout a relatively wide band in the audio frequency range.

If both tablets 86 and 87 are operated, it will be apparent that the sound produced will commence with a random noise sharp attack followed by a decaying string tone or flute tone, or both, simulating the tones produced by many mechanical musical instruments.

sistor R172 which is in series with a capacitor C174, and

thus impress a pulse upon a conductor 176. This conductor is connected to ground through a parallelly connected filter mesh comprising an inductance L178 and a capacitor C180. The conductor 176 is adapted to be connected to the collector conductor through a decoupling resistor R182, through closed switch 170. The pulse produced upon closure of switch 82, as filtered by the mesh L178 and C180, is thus impressed upon the input of amplifier 134, with the result that the speaker will produce a musically interesting tuned pulse such as is produced by the playing of a Chinese block.

It will be evident that the tablets 86, 87, and 88 may be operated individually or in any desired combination to produce a large variety of tonal effects.

In view of the fact that the operation of various portions of the circuit have previously been described, it is believed unnecessary to conclude this specification with a description of the operation of the instrument as a whole, except that it may be pointed out that depression of any of the playing keys 10, irrespective of whether any other key is at that time depressed, will cause energizetion of the relay winding L76 for a short period of time, with the result that one or more of the percussive circuits will be rendered effective to introduce a percussive attack, a random noise attack, or a Chinese block-like attack in' the tones produced. In addition, the signals from the oscillators will have their intensity envelopes controlled by the tubes 106 and 107. The value of the potential on terminal 118 may be adjusted to produce varij ous ratios of sustained and percussion output signals.

While I have shown and described a particular embodiment of my invention, it will be apparent to those skilled in the art that numerous modifications and variations may be made in the form and construction thereof, without departing from the more fundamental principles of the invention. I therefore desire, by the following claims, to include within the scope of my invention all such similar and modified forms of the apparatus disclosed, by which substantially the results of the invention may be obtained by substantially the same or equivalent means.

I claim:

1. In an electrical musical instrument having an output system including electroacoustic translating means, the combination of a plurality of electrical tone signal generators, each requiring the application of an electrical potential to an element thereof to render it operative to provide a tone signal, a source of potential of such value that when applied to the generator elements will render the generators operative, an impedance element, a manual comprising a plurality of playing keys, key operated switches, circuits including said switches in parallel and the impedance element in series for connecting the source respectively to the generator elements, a relay having a winding and a plurality of contactors closed in response to energization of the winding, electronic means responsive to a voltage drop across said impedance element to cause a pulse of current to flow through the relay winding sufficient to cause temporary closure of the contactors associated with the winding, a first intensity envelope control circuit, means coupling the outputs of the generators to the first intensity envelope control circuit, a second intensity envelope control circuit, a random noise generator coupled to the input of the second intensity control circuit, a tuned mesh, means responsive to the closure of two of the relay contactors to render the first and second intensity control circuits operative to transmit signals supplied thereto with a relatively sharp attack and slow decay, said third contactor operating to supply a voltage pulse to said tuned circuit, and means for selectively coupling the outputs of the first and second intensity envelope control circuits and the tuned circuit to the output system.

2. In an electrical musical instrument having an output system including electroacoustic translating means, the combination of a plurality of electrical tone signal generators, each requiring application of an electrical potential to an element thereof to render it operative to provide a tone signal, a source of potential of such value that when applied to the generator elements will render the generators operative, an impedance element, a manual comprising a plurality of playing keys, key operated switches, circuits including said switches in parallel and the impedance element in series for connecting the source respectively to the generator elements, a relay having a winding and a plurality of contactors closed in response to energization of the winding, electronic means responsive to change in voltage across said impedance element to cause a pulse of current to flow through the relay winding sufficient to cause temporary closure of the contactors associated with the winding, a first intensity envelope control circuit, means coupling the outputs of the generators to the first intensity envelope control circuit, a second intensity envelope control circuit, a random noise generator coupled to the input of the second intensity control circuit, means responsive to the closure of the relay contactors to render the intensity control circuits operative to transmit signals supplied thereto with a relatively sharp attack and slow decay, and means for selectively coupling the outputs of the first and second intensity envelope control circuits to the output system.

3. In an electrical musical instrument having an output system including electroacoustic translating means, the combination of a plurality of electrical tone signal generators, each requiring application of an electrical potential to an element thereof to render it operative to provide a tone signal, a source of potential of such value that when applied to the generator elements will render the generators operative, an impedance element, a manual comprising a plurality of playing keys, key operated switches, circuits including said switches in parallel and the impedance element in series for connecting the source respectively to the generator elements, a relay having a winding and a plurality of contactors operated in response to energization of the winding, electronic means responsive to a change in voltage across said impedance element to cause a pulse of current to flow through the relay winding suflicient to cause temporary operation of the contactors associated with the winding, an intensity envelope control circuit, means coupling the outputs of the generators to the intensity envelope control circuit, a tuned mesh, means responsive to the operation of one of the relay contactors to render the intensity control circuit operative to transmit signals supplied thereto with a relatively sharp attack and slow decay, another of the contactors operating to supply a voltage pulse to said tuned circuit, and means for selectively coupling the outputs of the intensity envelope control circuit and the tuned circuit to the output system.

4. An electrical musical instrument comprising a plurality of electrical tone signal generators of a type requiring the application of a potential thereto to render them operative, a keyboard comprising a plurality of playing keys, a source of potential, an impedance element, switches respectively operated by the keys and respectively connected to the generators, circuits connecting the switches in parallel and in series with the source and the impedance element, pulse producing electronic means operable in response to a decrease in voltage across the impedance element resultant from the closure of one of the key-operated switches even though other keys are depressed at the time, relay means coupled to the output of the electronic means and adapted to be momentarily energized by the pulses produced by the electronic means, percussive tonal envelope means, and an output system including electroacoustic translating means coupled to the output of the percussive tonal envelope means.

5. An electrical musical instrument comprising a plurality of electrical tone signal generators of a type requiring the application of a potential thereto to render them operative, a keyboard comprising a plurality of playing keys, a source of potential, an impedance element, switches respectively operated by the keys and respectively connected to the generators, circuits connecting the switches in parallel and in series with the source and the impedance element, pulse producing electronic means operable in response to a change in one sense only in the voltage across the impedance element resulting from operation of one f the key-operated switches even though other keys are depressed at the time, percussive tonal envelope means coupled to the output of the electronic means and adapted to be momentarily energized by the pulses produced by the electronic means, and an output system including electroacoustic translating means coupled to the output of the percussive tonal envelope means.

References Cited in the file of this patent UNITED STATES PATENTS 1,901,986 Ranger Mar. 21, 1933 2,233,258 Hammond Feb. 25, 1941 2,486,208 Rienstra Oct. 25, 1949 2,681,585 Hanert June 22, 1954 

